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EMBRYOLOGY 3: DEVELOPMENT OF THE LUNGS - Coggle Diagram
EMBRYOLOGY 3: DEVELOPMENT OF THE LUNGS
Canalicular(17-26 wks)
Terminal bronchioles>Resp. bronchioles>alveolar ducts(lined by cuboidal ep.:
Type 2 pneumocytes
>Surfactant)
Vascularization & Differentiation of epithelium(thins(flat squamous:
Type 1 pneumocytes
>gaseous exchange)
Terminal Sac Stage(27-38wks):
Saccules development
>lined by T1 pneumocytes>thin blood barrier>fibroblasts differentiate>collagen,elastin, ECM
Pseudoglandular (8-16 wks)
Terminal Bronchioles
Branching of lobes
Alveolar Stage(36-38wks)
Terminal sacs dived by 2ndary septae>mature alveoli>millions of alveoli via
septation
Lung maturation
Embryonic(4-7 weeks)
Bulging of Foregut>
Tracheobronchial diverticulum
>lung buds(primary bronchi)
Lung development in
aqueous environment
Liquid>proper lung dev. & prevent collapse
Trachea & Diaphragmatic movement>resist efflux of fluid(non breathing periods)
dependent on lung liquid frm pulmonary epithelium & amniotic fluid(swallowed)
Insufficient fluid(e.g. oligohydramnios)>
Pulmonary hyperplasia
as a result of renal agesis
Pulmonary Hyperplasia mechanisms
Space occupying lesions(e.g pleural effusion)
Changes in geometry
Musculoskeletal abnormalities of thorax>resist expansion
Congenital diaphragmatic hernis